74' F Engine Hesitation/Hard Start (1 Viewer)

[LR LC200]

Followed instructions on valve adjustment and happy with the result. While I was at it; pulled plugs and cleaned, adjusted plug gap to what's stated in Haynes Manual, adjusted points air-gap, cleaned up rotor, adjusted mixture, adjusted idle, and lastly adjusted timing. Rig runs much better at high end, in fact don't need to shift to 4th until 40 mph and can more comfortably go past 60mph, although I typically don't.

Only issue is hesitation from a standstill to where it stalled several times today and is much harder starting. Which of the above adjustments do you suspect is the culprit? Of all, the plug gap was the most surprising to me at 1.0 mm. Haynes lists it as spec for 78 USA model. Mine's a 74 of unknown origin. Don't know how to tell... PO Is a friend, and claims that it's a non-US unit.

 

[Curt]

Check your accelerator pump.

 

[LR LC200]

Ok, carb is a Rochester 2-Jet. Will have to look it up. Not real familiar with carbs, let alone accelerator pumps. No issues off the line previously and never a hard start. Often would fire without even pumping pedal...grant it she's in FL

 

[Curt]

if you take the air cleaner off and look down the carb you should see a stream of gasoline when the accelerator is pushed.

 

[Tancruiser]

I would suspect the timing did you use a light or set it by ear.

 

[65swb45]

Check your accelerator pump.

Second that.

 

[LR LC200]

I would suspect the timing did you use a light or set it by ear.

Set with light, dead-nuts on "BB."

 

[LR LC200]

if you take the air cleaner off and look down the carb you should see a stream of gasoline when the accelerator is pushed.

if you take the air cleaner off and look down the carb you should see a stream of gasoline when the accelerator is pushed.

Ok looked at that this AM. Steady stream when throttled at carb by hand, linkage is good.

If the plug gap is too big/coil is not strong enough, would that not cause hesitation with not enough spark?

 

[65swb45]

Low vacuum will cause hesitation.

What is your idle vacuum?

 

[LR LC200]

Low vacuum will cause hesitation.

What is your idle vacuum?

Don't have a gauge, but if I put my finger over the hose on the distributor end, it significantly lowers RPMs and wants to die...

 

[LR LC200]

Too large of a plug gap is not an issue, correct? Recall I made gap bigger... PO replaced plugs just before I bought it from him. So they were factory gapped Bousch until I changed it (smaller gap before).

 

[65swb45]

Don't have a gauge, but if I put my finger over the hose on the distributor end, it significantly lowers RPMs and wants to die...

Considering a vacuum advance signal is supposed to be non-existant at idle, that in itself raises questions.

 

[LR LC200]

Overall it runs much better, but I don't know if I can attribute that to adjusting the valve lash... It use to miss consistently. I adjusted the timing a little to where the BB is now below (towards the bottoms of the window) The pointer by about a half inch. Don't know if that's advance or retard. Will see if it runs better that way. Also weird start now. Turn key, starter wines away, but won't start until I release the key from start position. Then it sputters, picks up RPMs, and runs normal...

 

[Curt]

The BB is 7* and the factory timing mark, It sounds like you have advanced the timing if the BB gets lower in the window. This may not be bad, some run the 2f with more advance 10* or more.

I agree with 65swb45 thats a problem.

Whats your idle mixture set at, what kind of carb tune did you do. When was it last rebuilt.

 

[LR LC200]

Running a F engine on this 74' although one guy thought it was a 1.5F; havent read up on how to tell the difference... Original owner, two ago, put a Rochester 2-jet on it. I tuned by turning the left mixture screw clockwise until hit highest rpms and started to drop. Then did same on right mixture screw. Lastly adjusted idle up until smooth. Do you suggest an alternate method?

 

[65swb45]

There is an order to things.

If you insist on moving forward without complete diagnostic tools, I'm sure someone will assist you with wild ass guesses. If you want solid advise, IMO you need to get testing equipment, provide messurements. Others before you have worn out their welcome by insisting on asking question after question that only evidences lack of real commitment to the process. I'm not saying that's you, but I am taking a minute to suggest you take some steps to prevent that appearance.

Post links to the threads you have researched on this subject. What is your ETA on receiving your test equipment? I have helped diagnose thousands of vehicle issues on this forum, and continue to willingly do so to those who demonstrate commitment and a degree of discretion to the process.

Best

Mark

 

[LR LC200]

Mark- Understand. Thanks for the suggestion.

Rick

 

[Curt]

Get a vacuum gauge for sure, check out carb tuning tips on the forum.
Carb Works Great!

Many prefer the stock carbs on these f engines, maybe something to look into.